Chemical composition and antifungal effect of Saccharomyces boulardii extract against Candida albicans clinical isolates

The use of high amounts of a variety of antifungal drugs for treatment of Candida albicans infections is effective in inducing resistance to these drugs. Saccharomyces boulardii is a non-pathogenic yeast used as a probiotic in prevention and treatment of diarrhea diseases. There is evidence of the inhibitory effect of this yeast on Candida albicans virulence factors.
Saccharomyces boulardii extract was obtained from filtered culture in YNB and PDB culture media. Antifungal activity of S. boulardii extract against C. albicans (fourteen clinical isolates and standard strain ATCC10231) was performed by the micro broth dilution method according to M27-A3 CLSI. The chemical composition of the extract was determined by the GC/MS method.
Dry substance obtained from 1 liter of YNB culture was 20 mg/ml whereas that of PDB culture was 50 mg/ml. S. boulardii extract did not show any fungicidal and inhibitory effect against C. albicans isolates. Substances obtained from PDB and YNB cultures and used in this experiment showed similar results. Eleven compounds representing 86.18 % of the extract were identified. The major constituents of yeast extract were Tyrosol (37.08%) and Phenylethyl Alcohol (26.75%).
The major constituents of yeast extract were Tyrosol (37.08%) and Phenylethyl Alcohol (26.75%). This study confirms that S. boulardii extract did not show any fungicidal and inhibitory effect against C. albicans isolates.